Six-year overhaul of I-5 in Tacoma about to start

As contractors check off the final details on Tacoma’s massive Nalley Valley interchange this month, another even bigger series of freeway construction projects is coming down the road.

The state Department of Transportation is about to embark on a six-year makeover of Interstate 5 through downtown Tacoma, a $723 million effort that will add car pool lanes, renovate all driving surfaces and replace two bridges across the Puyallup River.

The four-mile stretch of I-5 from Fife past the Tacoma Dome to South M Street is Pierce County’s busiest freeway, with an average daily traffic count of 158,000 vehicles.

Engineers warn that the volume of traffic and the snarl of exits and ramps associated with intersections with Interstate 705 and state routes 7 and 167 will make the renovation a challenging exercise in orchestrating traffic flow.

At a July 10 groundbreaking ceremony for the first phase of the project — broadening the freeway between South M Street and Portland Avenue — the Transportation Department’s Olympic Region administrator, Kevin Dayton, called the job “a traffic-control project with a little bit of construction.”

Dayton was joking, but he had a serious point. Nearly all construction will take place alongside and above heavy traffic, requiring numerous lane closures and detours.

“I will not pretend there will be zero delays,” said Max Kuney, president of Max J. Kuney Construction, which won the bid for the M Street to Portland Avenue job. “But I promise to keep them as short as possible.”

The Transportation Department has divided the freeway makeover into three contracts.

The first, which Kuney won with a bid of just over $98 million, entails removing and replacing two busy freeway overpasses — Pacific Avenue and McKinley Way — and carving out space for new lanes in hillsides adjacent to existing northbound I-5 lanes.

The new overpasses will have longer spans to accommodate more lanes of traffic beneath them.

The second contract is expected to go to bid in early September and run concurrently with the M Street to Portland Avenue project. It will consist primarily of building a new northbound bridge over the Puyallup River.

The third contract entails removing both existing I-5 bridges and building a new southbound bridge.

Overpasses

Initially, the most significant impact to traffic will be the closures of the Pacific and McKinley overpasses, which connect downtown Tacoma with the East Side.

Both will be dismantled and replaced. The closures will occur sequentially: While one overpass is out of commission, detours will direct traffic onto the other.

The Pacific Avenue overpass, the busier of the two with 15,000 vehicles a day, is scheduled to close for 11 months beginning in October or November.

When it partially reopens in the fall of 2015, the McKinley overpass, which currently carries 4,300 vehicles a day, will shut down for 18 months.

The old overpasses will be removed by cutting them into sections small enough to be lowered by cranes to the freeway and hauled away, according to Jon Deffenbacher, the Transportation Department’s project engineer.

Most of that work will be done at night, Deffenbacher said, to minimize the effects on traffic.

In addition to having longer spans, the new overpasses will be wider. The one on Pacific will have a 14-foot-wide bike and pedestrian sidewalk on its northbound side and a six-foot-wide sidewalk on the southbound side.

When the McKinley overpass reopens in 2017, it will have six-foot-wide bike lanes and 10-foot-wide sidewalks on both sides.

As the overpasses are being demolished and rebuilt, crews will make room for three new traffic lanes on I-5 by removing 230,000 cubic yards of earth (the equivalent of about 23,000 dump-truck loads) adjacent to existing northbound I-5 lanes and stabilizing the cut with retaining walls.

During the project, crews will remove and replace the concrete driving surface, which has been in place since the freeway was constructed in the 1960s.

Traffic effects

The Transportation Department isn’t planning to reduce speed limits on I-5 during construction, according to Claudia Bingham Baker, an agency spokeswoman, but she said traffic most likely will move more slowly anyway.

Lanes will be narrowed, alignments shifted and shoulders reduced to two feet during construction, she said. That, combined with the visual distraction of ongoing construction, is likely to make drivers ease up on the gas.

“People tend to naturally slow down in situations like this,” she said, “but the speed limit won’t change.”

Lanes currently used for northbound traffic eventually will become carpool lanes, but not for years. They won’t open until the new bridges over the Puyallup are finished — in 2020, if all goes well.

“We’re not going to see the dramatic improvements, like when we opened the Narrows Bridge,” Bingham Baker said. “This is a piece of the overall vision.”

“This portion of I-5 will feel better,” she said. “There will be improved lighting and improved storm-water treatment. It will be smoother. There will be a lot of subtle benefits. But we’re not adding general purpose capacity.”

“The real difference,” Bingham Baker said, “will come when we’re able to open the HOV (high-occupancy vehicle) lanes to the north and south.”

Construction of a new HOV viaduct in the Nalley Valley, south of the I-5 projects, is expected to start in 2020. The estimate completion date is 2022.

Statewide, the Transportation Department has built 317 miles of HOV lanes and has another 45.5 miles planned. Almost all are in King and Snohomish counties.

Pierce County’s first HOV lanes opened in 2007, on the stretch of state Route 16 from Union Avenue in Tacoma to Olympic Drive in Gig Harbor. The first HOV lanes on I-5 in Pierce County opened in 2010, along three miles extending from the King County line to the Port of Tacoma Road.

“We’re a little late being asked to the party,” Deputy Pierce County Executive Kevin Phelps said at the groundbreaking ceremony for the M Street to Portland Avenue project. “But we’re very glad to be here.

“Anybody who’s traveled from the King County line or across the Narrows Bridge has seen the difference in safety that HOV lanes make.”

In 2023, when the Tacoma/Pierce County HOV system is complete, Bingham Baker said, drivers will be able to travel in carpool lanes from Gig Harbor all the way to Everett.

Pollutant solutions

In the meantime, Deffenbacher said, the M Street-to-Portland Avenue project will be complicated by the need to remove contaminated soil the Transportation Department disposed of in concrete-lined vaults during an earlier construction project.

The soil was contaminated with petroleum products from an old gasification plant that was excavated when the Tacoma Spur (I-705) was being constructed in 1988.

Rather than hauling the soil to a waste facility, the state decided to isolate and bury it.

“At the time it was an economic and creative way to handle the problem,” Bingham Baker said. “We didn’t envision we would need that land again.”

The soil in two of the vaults, each about 100 feet wide, 230 feet long and 18 feet deep, was removed last year.

In the course of the M Street-to-Portland Avenue project, another 7,000 cubic yards of contaminated soil will need to be excavated and hauled away.

Another unseen improvement will involve storm water disposal. Polluted runoff from the freeway flows into the Thea Foss Waterway, a Superfund site that cost millions to clean.

When the freeway projects are finished, runoff will be treated with filter drains, settlement ponds and landscaping designed to remove pollutants, Bingham Baker said.

Bridge projects

Construction of the northbound I-5 bridge across the Puyallup River got a jump start four years ago, thanks to federal stimulus funds.

The Transportation Department completed a six-story earthen structure near the Puyallup Tribe’s Emerald Queen Casino that will become the northbound bridge abutment on the Tacoma side of the river.

Further work on the bridge projects was stalled for two years because of a breakdown in negotiations with the tribe. The bridges and their approaches will cross land the tribe regards as culturally significant, and construction potentially could endanger fish habitat.

The tribe’s biggest concerns have been protecting water quality, maintaining access for Puyallup fishermen and ensuring that culturally significant property will be treated with respect, tribal spokesman John Weymer said.

In July, the Transportation Department at last signed an agreement with the tribe, but the details have not been released, pending a review by the state Attorney General’s Office.

If the agreement becomes official, Bingham Baker said, the contract for the northbound bridge project will go to bid Sept. 8. Construction would likely begin in January 2015, she said, and reach completion in 2018.

Total cost for the northbound bridge project is estimated at $305 million, funded by proceeds from the 2005 gas tax. Cost for the southbound bridge project is estimated at $250 million.

The Transportation Department says the delay caused by negotiations with the tribe increased the cost of construction by about $20 million.

State engineers have devised a complex traffic shuffle to accommodate drivers during bridge construction.

Both northbound and southbound I-5 traffic will be shifted temporarily onto the new northbound bridge while crews build the new southbound bridge and demolish and remove the current bridges.

HOV lanes will open only after both new northbound and southbound bridges are complete in 2020.

The new bridges will be straighter and wider than the existing bridges, according to the state’s plans, and their alignment will be tipped slightly southeast to flatten the freeway’s curve as it crosses the river.